Diazonamide A is a mitotic spindle-disrupting agent first isolated from the marine organism Diazona angulata, having the structure:

Numerous attempts have been made to synthesize this compound and its analogs. PCT publication WO 03/106438 describes a putative synthetic route; however, the structure identified as diazonamide A provided in that publication is incorrect. U.S. Pat. No. 7,022,720 correctly discloses the structure of diazonamide A and describes the synthesis of some of its analogs through the combined use of catalytic Heck endocyclization, stereo-controlled ring-contracting Pinacol rearrangement, and indole arylation via internal photo-induced electron transfer. Generic structures of some analogs are provided. U.S. Ser. No. 11/264,502 was filed 31 Oct. 2005 as a continuation-in-part of U.S. Ser. No. 10/227,509 (now U.S. Pat. No. 7,022,720), and is published as US 2006/0089397. U.S. Ser. No. 11/591,016 was filed 31 Oct. 2006 as a continuation-in-part of U.S. Ser. No. 11/264,502 (pending), and is published as US 2007/0149583.
In spite of considerable synthetic efforts, there is still a need to discover improved, more efficient processes and novel intermediates for use in the synthesis of diazonamide analogs.